Lab 1: Laboratory Skills, Measurement, Microscope

Question 1

Accurate lab equipment

Answer 1

Volumetric flask, burette, graduated glass pipettes, graduated cylinders

Question 2

5 % error lab equipment

Answer 2

Erlenmeyer flask, beakers

Question 3

Not accurate lab equipment

Answer 3

Disposable ungraduated plastic pipette, ungraduated glass pipettes.

Question 4

Using a graduated cylinder - meniscus

Answer 4

Water is a polar molecule and it adheres to the sides of the cylinder, creating a concave shapes meniscus. Always read the bottom of the meniscus.

Question 5

Conversion Factors

Answer 5

1g=1000mg

1L=1000ml

Question 6

Length

Answer 6

km: dimensions of a building or distance between cities
m: height or size of a room
cm: length of a table or a book or size of a mole or tumor
mm: thickness of skin or hair

um or u: (micrometer) describe a cell size; 1m=1,000,000u

Question 7

Compound Microscope

Answer 7

2 lenses (ocular and objective) magnify the image

Question 8

Light

Answer 8

visible light is the source of ilumination

Question 9

Binocular

Answer 9

2 eyepieces (ocular)

Question 10

How to carry a microscope?

Answer 10

Carry the microscope with two hands, one on the arm, the other on the base.

Question 11

Arm, base

Answer 11

support structures

Question 12

Stage

Answer 12

where you put the slide, there’s a mechanical stage with a clip to hold the slide and the stage adjustment knobs to move the slide

Question 13

Ocular lens

Answer 13

magnifies the image, usually 10x, pointer glued on lens

Question 14

Objective lenses

Answer 14

On the rotating nose piece.

1. Scanning lens: 4x
2. Low magnification lens: 10x
3. High dry lens: 40x
4. Oil immersion lens: 100x

Question 15

Coarse and fine adjustment

Answer 15

Focus the image

Question 16

Iris Diaphgram

Answer 16

opens and closes to adjust AMOUNT of light on the condenser lens

Question 17

Condenser lens

Answer 17

Focuses the beam of light

Question 18

Rheostat

Answer 18

adjusts BRIGHTNESS of light

Question 19

Total magnification

Answer 19

ocular power x objective power

Question 20

Procedure to focus a slide

Answer 20

• Scanning lens clicked into position
• Stage all the way up
• Specimen centered
• Slowly turn the coarse adjustment knob until image is in focus
• Sharpen focus with fine adjustment

Question 21

Note changes when you increase the magnification

Answer 21

• The higher the magnification, the more detail you see in the specimen
• The higher the magnification, the smaller the field
• More light with higher magnification

Question 22

Image in inverted

Answer 22

Image is inverted:

upside down and backwards

Question 23

How to put microscope back correctly

Answer 23

• Slide off
• Lenses wiped clean
• Light shut
• Stage all the way down
• Cord wrapped neatly
• Scope put in the correct number